KTimer - KTimer is a little tool to execute programs after some time.
Talalarmo - Minimalistic android alarm
T-Clock Redux - T-Clock Redux in an enhanced fork of Stoic Joker's T-Clock 2010 with ISO week number support...
Date Reminder - Date Reminder reminds you of recurring or nonrecurring events, like birthdays, bills to pay...
Insane Alarm - Wakes you up no matter what! Features - obscenely loud blaring emergency alarm sound.
Alarm Clock (applet) - Alarm Clock is a fully-featured alarm clock for your GNOME panel or equivalent.